Electrically heated key



Feb. 20, 1962 R. w. WAGNER 3,022,408

ELECTRICALLY HEATED KEY Filed Oct. 25, 1960 FIG.4

INVENTOR. ROBERT W WAGNER ATTORNEYS United States Patent Office3,022,408 Patented Feb. 20, 1962 ELECTRICALLY HEATED KEY Robert W.Wagner, 1102 Lowenhill St., Pittsburgh, Pa. Filed Oct. 25, 1960, Ser.No. 64,806

6 Claims. (Cl. 219-49) This invention relates to a device for boththawing and unlocking frozen locks, and more particularly to a keyhaving an electrical heating element therewithin for facilitating theopening of frozen locks.

Past endeavors to overcome the problem of opening frozen locks haveincluded devices for surrounding the entire lock structure withintegrally formed heating elements, heating the key in a separatefurnace-like apparatus prepearatory to inserting it Within a lock, andinserting a small and ineffective wire-like heating element within thelock before applying the key thereto. None of the above previouslysuggested devices are completely satisfactory, however, due to one ormore disadvantages inherent in each. For instance, where the lock,itself, is supplied with a heating element integrally therewith, theheating element is not normally energized until the key isfully insertedWithin the lock. Therefore, where the look entrance, itself, is frozen,it is impossible to even insert the key within the lock and accordinglythe heating element cannot be energized. Further, such installations arecostly, since each lock must be provided with a heating element in closeproximity to the tumblers, special insulation about the heating element,and special electrical installation for energizing the heating element.

Where the separate heating apparatus is employed to firstheat .the' keybefore inserting it within the look, not only is a time delayencountered while the key is being heated within the separate unit, butalso a large portion of the residual heat of the key is lost when it isbeing transferred from the heating unit to the lock. Further, when thelock is badly frozen, it is necessary to re-heat the key several timesin order to thaw out the lock, thus entailing 'a rather time-consumingand exasperating operation.

When the thin wire-like heating element device is utilized to thaw out alock preparatory to the insertion of a key, the wire forming the heatingelement does not simultaneously fully contact the entire interiorsurface of the lock, since the wire, by necessity, must be quite thin soas to fit a plurality of different locks. Accordingly, in order to thawout all of the tumblers, it is necessary to re-position the heatingelement within the lock several times. Further, due to the'extremelysmall mass involved in the Wire heating element, -a rather lengthy timeis necessitated in order to completely thaw out the lock beforeinserting the key. Then too, it will be apparent that this procedurerequires a two-step operation of first inserting a heating element andthen quickly inserting a key before the lock has had an opportunity torefreeze.

I have found that optimum thawing conditions for frozen locksareobtainable by supplying a heating element directly within the nose ofa key in such a manner so that the element transmits heat through thenose of the key and into the lock, thus permitting the lock to bequickly and efiiciently thawed out and opened in one operation.

It thus has been an object of my invention to provide a simple andefiicient device for overcoming the problems heretofore involved infreeing frozen looks;

A further object of my invention has been to provide a new article ofmanufacture which may both thaw and open a frozen lock;

An additional object of my invention has been to provide an electricallyheated key for thawing and unlocking frozen or jammed locking devices;

A still further object of my invention has been to pro vide a standardkey with an electrically resistant portion connected to a source ofelectrical power wherein the resistant portion transforms electricalenergy into heat energy to thaw out a lock;

Another object of my invention has been to provide a key with anelectrically resistant heating element in the nose portion thereof fortransmitting heat through the key to the internal mechanism of a lock,and with a disc portion adjacent the back end of the nose portion fortransmitting heat from the key to the end of the look cylinder in whichthe key is inserted.

These and other objects of my invention will be apparent to thoseskilled in the art from the following disclosure and accompanyingdrawings in which:

FIGURE 1 is a perspective view of an electrically heated key embodyingmy invention;

FIGURE 2 is an enlarged sectional view of the key taken along lines 2-2of FIGURE 1;

FIGURE 3 is a sectional view in elevation on the 7 same scale as FIGURE2 and taken along lines 3-3 of FIGURE 2; and

FIGURE 4 is a sectional view in elevation on the same Scale as FIGURE 2and taken along line 4-4 of FIGURE 2.

I have found that a definite need still exists for a solution to theproblem of frozen locks. Utility companies, for example, such aselectric companies, gas companies, and railroads, have manysub-stations, pumping stations, inplement housings, and other suchoutposts, which must be periodically checked by service and maintenancepersonnel. These sub-stations or outposts are necessarily kept locked,and it is common practice for such companies to utilize a standard lockon each of its sub-stations so that the service or maintenance personnel need only utilize one master key to open all of the facilitiesWithin their charge. Although integral locks may be utilized, padlockshave been found to be the most economical means for locking theseoutposts, especially since it is desirable to periodically change thelocks. Since the locks are necessarily exposed to the weather, theyreadily become frozen during the inclement winter months, and impedeaccessibility to thesub-stations during that time of the year when themaintenance requirements are usually the highest.

To alleviate this problem, I have devised an electrically heated masterkey which may be utilized for the standard locks on all sub-stations orother such outposts in a certain area or Within the charge of certaindesignated personnel. The electrically heated key is easily portable,and may be adapted to operate from portable cells, an automobilebattery, or a standard household outlet. When the key is operated froman automobile battery, I have found that it is convenient to mount aself-winding spool adjacent the battery for facilitating the feeding:out and reeling-in of the leads connecting the key to the battery. 1

Referring now to the drawings, a key 10 embodying my invention has ahandle portion .11 and a shank or nose portion 12. A disc or platemember 13 is provided on a back portion of the shank 12 adjacent thehandle: portion 11, and may either be formed integrally with the key 10or welded thereon such as shown at w in FIG- URE 2.

A longitudinally-extending slotted or grooved portion 14 is formed inthe shank or nose portion 12, and as shown particularly in FIGURES 2 and4, may extend completely therethrough. An electrically resistant heatingelement 15 formed of any suitable high resistant material, such asnickel-chrome alloys, is positioned within the slotted porton 14. Oneend of the heating element is secured at 16 to a forward end of theslotted portion 14, such as by crimping, welding, or soldering.

A cut-out or recessed portion 17, formed in a forward portion of thehandle portion 11, communicates with the groove or slotted portion 14.As shown particularly in FIGURE 2, the rearward end of the heatingelement 15 projects Within the recessed portion 17 and is connected toan end of an electrical lead 18, such as by welding or soldering. Thelead 18, having an insulated cover 13', also extends into the recess 17.An insulating cement or mastic material 19 not only surrounds andinsulates the rearward end of the heating element 15 and the connectionbetween the heating element and the lead 18 from the key body, but alsoretains the rearward end of the heating element in position within therecess 17. Accordingly, the rearward end of the heating element 15 andits connection with the lead 18 are electrically insulated from the key,proper, so that current cannot pass directly between the rearward end ofthe heating element and the body of the key. As can be seen from thedrav ing's, and particularly FIGURES 2 and 4, the heating element 15 ispositioned within the slotted portion 14 in such a manner so that itdoes not contact the key along its extent, but only at theforwardconnection 16. v

A switch contact 20 projecting outwardly from a side face of the handleportion 11 extends inwardly into a recess 20 formed within the handleportion. An electrical lead 21 having an insulating cover 21 alsoextends within the recess 20 and is suitably connected to the switchcontact 20. Insulating material 22,- pos'itioned within the recess 20,surrounds and insulates the connection between the switch contact 20 andthe lead 21 and the contact 20 from the body of the key.

A resilient U-sha'ped switch 23 is secured along one leg 24, such as bywelding or soldering, to a side of the handle body. An opposite side leg25 is normally resilieritly urged in an open or outwardly-spaced-apartposition from the switch contact 20, as shown in full lines in FIGURES 2and 3. The switch, however, may be closed by compressing the leg 25inwardly into engagethem with the switch contact 20 as shown in chainlines in FIGURES 2 and 3. The leg 25 is provided with an insulated covermember 26.

The key 10 may be provided with a standard hole 27 extending through thehandle portion 11. The leads 18 and 21 are connected to opposite sidesof a suitable source of electrical power and may enter a rearwardportion of the key along a grooved or recessed portion 28 formed in thehandle portion 11. The lead 21 then passes through the hole 27 into therecess 22 wherein it is connected to the switch contact 20-. The lead 18extending forwardly to the rearward portion of the heating element 15may lie within a groove 29 also formed in the handle portion 11. Thehandle portion has an outer layer of insulating material 30 which mayeither be of a rubber-like composition of a ceramic material. Ifdesired, the leads 13 and zrmay be imbedded within the insulatingmaterial 30 of the handle portion 11 instead of being positioned withinthe grooves 28 and 29 formed in the handle body. Also, the rearward faceof the disc 13 may be provided with insulating material to direct theheat forwardly and to further protect the user from the heat of the key.

In operation, with the leads connected to a suitable source ofelectrical power, the key may be inserted within the lock before closingthe switch, or, more preferably, the switch is closed as soon as the keyis grasped and then inserted within the lock. I have found that afterthe switch is closed, the heating element reaches a cherry redtemperature in about five seconds. When the switch is closed, currentpasses from inlet lead 21 through the contact 20, the switch 23,forwardly through the nose portion 12 and backwardly through the heatingelement 15 to outlet lead 18. The heat derived from the heating elementis transmitted through the nose of the key and contacts all of thetumblers in the lock simultaneously so that the internal mechanism ofthe lock receives an even distribution of heat from the key, thusquickly and efiiciently thawing it out. In addition, the disc or platemember 13, being formed of a good heat conductor such as brass orcopper, transmits heat from the shank of the key to the end of thecylinder in which the key is inserted, thereby greatly enhancing thethawing of the lock.

Although I have disclosed and described a preferred embodiment of myinvention, it will be apparent to those skilled in the art that variouschanges and modifications may be made thereto without departing from thespirit and scope of the invention, as defined in the appended claims.

What I claim is:

1. An improved key for both thawing-out and unlocking a frozen lockcomprising a handle portion, a nose portion and a heat conductive discmember formed on said nose portion adjacent said handle portion, aslotted portion extending longitudinally along said nose portion, aheating element positioned within said slotted portion, means forconnecting said heating element to a source f electrical power, and aswitch secured to said handle portion and forming a part of said meansfor energizing said heating element to heat the nose of said key andsaid heat conductive disc member for efficiently transferring heat tothe tumbler and lock cylinder of a frozen lock.

2. An improved key for both thawing and unlocking a frozen lockcomprising a handle portion, a nose portion, and a disc member of heatconductive material formed on said nose portion adjacent said handleportion with a forward face of said disc member being normal to thelongitudinal axis of said nose portion, a longitudinally-extendingslotted portion formed in said nose portion, a recess formed in saidhandle portion adjacent said slotted portion, an electrically resistantheating element positioned within said slotted portion with one end ofsaid heating element being secured to said nose portion at the forwardend of said slotted portion, and the other end of said heating elementprojecting into said recessed portion, means projecting within saidrecessed portion for connecting said other end of said heating elementto one side of a source of electrical power, means for electricallyinsulating said other end of said heating element from the body of saidkey, means connecting said one end of said heating element to anopposite side of the source of electrical power, and said heatingelement, except for its connection with the forward end of said slottedportion, being spaced-apart from said nose portion along its extent.

3. An improved key assembly for both thawing and unlocking a frozen lockcomprising a handle portion and a nose portion, a heat conductive discmember formed on said nose portion adjacent said handle portion, anelectrically resistant heating element positioned within said noseportion for heating both said nose portion and said disc member totransfer heat simultaneously to the tumblers and end face of a lockcylinder, said. heating element being electrically connected to said keysolely at a forward end of said nose portion, means forming a circuitfor connecting said heating element to opposite sides of a source ofelectrical power, said means comprising an electrical conduit connectingone side of the source of electrical power to a rearward end of saidheating element, a normally open switch secured to one side of saidhandle portion, a second electrical conduit connecting the other side ofthe source of electrical power to a switch contact insulatablypositioned on said handle portion, and said switch when in a closedposition completing the circuit between the source of power and saidheating element so that current may flow through the switch, the nose ofthe key, and the heating element to thereby energize said heatingelement.

4. An improved key assembly as defined in claim 3 wherein saidelectrical conduits formed in said handle portion.

5. An improved key assembly as defined in claim 3 wherein outer surfaceportions of said handle portion are of insulating material to protectthe user from both shock and heat.

6. An improved key for both thawing and unlocking a frozen lockcomprising a handle portion, a nose portion, and a heat conductivemember secured to said nose portion adjacent said handle portion forcontacting and heating the end face of a lock cylinder, a heatingelement positioned within and extending along said nose extend alongrecesses UNITED STATES PATENTS 944,382 Ross Dec. 28, 1909 2,538,872Jones Jan. 23, 1951 2,774,855 Simmons Dec. 18, 1956 2,863,036 Mitchellet a1. Dec. 2, 1958 2,965,741 Blazina Dec. 20, 1960

